ILHELM] (1823– 1883), British inventor, engineer and natural philosopher, was born at Lenthe in Hanover on April 4, 1823. After being edu cated in the polytechnic school of Magdeburg and the University of Gottingen, he visited England at the age of nineteen in the hope of introducing a process in electroplating invented by himself and his brother Werner. The invention was adopted by Messrs. Elk ington, and Siemens returned to Germany to enter, as a pupil, the engineering works of Count Stolberg at Magdeburg. In 1844 he was again in England with another invention, the "chronometric" or differential governor for steam engines. Finding that British patent laws afforded the inventor a protection which was then wanting in Germany, he thenceforth made England his home ; in 1859 he became a naturalized British subject. After some years spent in active invention and experiment at mechanical works near Birmingham, he went into practice as an engineer in 1851. He worked mainly in two distinct fields, the applications of heat and the applications of electricity. Siemens became F.R.S. in 1862; he was president of many professional societies and the recipient of academic honours. He died in London on Nov. 19, 1883.
In the application of heat Siemens's work began just after J. P. Joule's experiments had placed the doctrine of the conserva tion of energy on a sure basis. Siemens, in the light of the new ideas, sought to improve the efficiency of the steam engine as a converter of heat into mechanical work. He applied the regenerator to the steam engine and later he attempted to apply it to internal combustion or gas engines. In 1856 he introduced the regenerative furnace, the idea of his brother Friedrich (1826 1904), which avoids the loss of heat by the hot gases which pass up the chimney. But another invention was required be fore the regenerative furnace could be thoroughly successful. This was the use of gaseous fuel, produced by the crude distilla tion and incomplete combustion of coal in a distinct furnace or gas-producer. The complete invention was applied at Chance's glass-works in Birmingham in 1861, and furnished the subject of Faraday's farewell lecture to the Royal Institution. It was soon applied to many industrial processes, but it found its greatest development a few years later at the hands of Siemens himself in the manufacture of steel. To produce steel directly from the ore, or by melting together wrought-iron scrap with cast-iron upon the open hearth, had been in his mind from the first, but it was not till 1867, after two years of experiment in "sample steel works" erected by himself for the purpose, that he achieved success. The product is a mild steel of exceptionally trustworthy quality, the use of which for boiler-plates has done much to make possible the high steam-pressures that are now com mon, and has consequently contributed, indirectly, to the im provement in the thermodynamic efficiency of heat engines. Just before his death Siemens was at work on a plan to use gaseous fuel from a Siemens producer in place of solid fuel beneath the boiler, and to apply the regenerative principle to boiler furnaces.
He believed that gaseous fuel would in time supersede solid coal for domestic and industrial purposes; and among his last inven tions was a house grate to burn gas along with coke, which he regarded as a possible cure for city smoke.
In electricity Siemens's name is closely associated with the growth of land and submarine telegraphs, the invention and de velopment of the dynamo, and the application of electricity to lighting and to locomotion. In 186o, with his brother Werner, he invented the earliest form of what is now known as the Siemens armature; and in 1867 he communicated a paper to the Royal Society "On the Conversion of Dynamical into Electrical Force without the aid of Permanent Magnetism," in which he announced the invention by Werner Siemens of the dynamo-electric machine, an invention which was also reached independently and almost simultaneously by Sir Charles Wheatstone and by S. A. Varley. The Siemens-Alteneck or multiple-coil armature followed in 1873. While engaged in constructing a trans-Atlantic cable for the Direct United States Telegraph Company, Siemens designed the very original and successful ship "Faraday," by which that and other cables were laid. One of the last of his works was the Portrush and Bushmills electric tramway, in the north of Ireland, opened in 1883, where the water-power of the river Bush drives a Siemens dynamo, from which the electric energy is conducted to another dynamo serving as a motor on the car. In the Siemens electric furnace the intensely hot atmosphere of the electric arc between carbon points is employed to melt refractory metals. Another of the uses to which he turned electricity was to employ light from arc lamps as a substitute for sunlight in hastening the growth and fructification of plants. Among his miscellaneous inventions were the differential governor, and a highly scientific modification of it, described to the Royal Society in 1866; a water-meter which acts on the principle of counting the number of turns made by a small reaction turbine through which the supply of water flows ; an elec tric thermometer and pyrometer, in which temperature is de termined by its effect on the electrical conductivity of metals; an attraction meter for determining very slight variations in the in tensity of a gravity; and the bathometer, by which he applied this idea to the problem of finding the depth of the sea without a sounding line.
Siemens's writings consist for the most part of lectures and papers scattered through the scientific journals and the publica tions of the Royal Society, the Institution of Civil Engineers, the Institution of Mechanical Engineers, the Iron and Steel Institute, the British Association, etc.
See William Pole's Life of Siemens (1888). (J. A. E.)